It's true that rubber bands are in-expensive, but then why be wasteful? I use the baby powder in a container to store my used bands. When putting the bands on the plane, I check each one for tears etc. Any rubber bands that don't look or feel good are discarded. Also, I tend to use plenty of rubber bands that if a couple break, I would still not have any problems. Also, it's a good idea to use a few new rubber bands with the rest of the old ones.

Typically, on my eagle II, I use about 8 rubber bands per side which is plenty. Have never had a wing failure in over 5 years and hundreds of flights.